THE SKELETON AND TEETH
narrow cleft. Several important foramina are seen on the posterior wall. The optic foramen is separated from the wide anterior lacerate foramen bv a thin
septum; and the foramen rotundum is very obtrusive below these. The foramen rotundum is not always seen in the orbit in the Gibbons. On the floor of the orbit there is a wide, shallow trough for the infra-orbital vessels and nerve; and the beginning of the canal for the naso-lachrymal duct is a marked feature on the inner wall. The entire orbit has a relatively smaller capacity than in the Gibbons.
The anterior narial aperture is pyriform, with the narrow end above. It is bounded as in the Gibbons, but the area occupied by the free edge of the fused nasal bones is very much smaller. The Orang, in fact, has narrower nasal bones than all other Anthropoids, and the fused mass forms a long, narrow splint (fig. 21). The anterior nasal spine is absent, or represented by a slight median ridge. Occasionally a groove runs along the mid-line from the space between the two upper incisor teeth to the root of the septum nasi. On looking into the narial aperture the turbinate bones are seen.
The infra-orbital foramina vary. Thus in one skull
there were three small foramina in a horizontal line on one side, and two large openings on the other. No supra-orbital foramen is present.
Norma Lateralis.—The zygomata are bent outwards and the alisphenoid is channelled, so the infra-temporal fossa is deep. The pterion is composed, as in the Gibbons and Man, by the articulation of the parietal and alisphenoid. In this respect the Asiatic Simiidse 8